U.S. patent application number 11/547177 was filed with the patent office on 2009-02-26 for jig.
This patent application is currently assigned to EASTLAND MEDICAL SYSTEMS LTD.. Invention is credited to Philip Bunce.
Application Number | 20090053979 11/547177 |
Document ID | / |
Family ID | 35063593 |
Filed Date | 2009-02-26 |
United States Patent
Application |
20090053979 |
Kind Code |
A1 |
Bunce; Philip |
February 26, 2009 |
Jig
Abstract
A jig intended in use to hold a set of blanks of rod-like or
wire-like form during machining, said jig having a body adapted to
be mounted to a drive shaft for rotation of the body about an axis
of rotation, the body having an outer portion and an inner portion
wherein the inner and outer portions are capable of angular
displacement relative to each other, the portions having opposed
faces which are concentric and which define clamping faces which in
use are intended to support the set of blanks such that their
central axes are substantially parallel to the axis of rotation and
at least one end extends axially beyond the body.
Inventors: |
Bunce; Philip; (Victoria,
AU) |
Correspondence
Address: |
MERCHANT & GOULD PC
P.O. BOX 2903
MINNEAPOLIS
MN
55402-0903
US
|
Assignee: |
EASTLAND MEDICAL SYSTEMS
LTD.
Western Australia
AU
|
Family ID: |
35063593 |
Appl. No.: |
11/547177 |
Filed: |
March 24, 2005 |
PCT Filed: |
March 24, 2005 |
PCT NO: |
PCT/AU05/00432 |
371 Date: |
September 8, 2008 |
Current U.S.
Class: |
451/374 |
Current CPC
Class: |
B23B 31/16275 20130101;
B24B 19/16 20130101; B24B 41/06 20130101 |
Class at
Publication: |
451/374 |
International
Class: |
B24B 19/00 20060101
B24B019/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 31, 2004 |
AU |
2004901713 |
Claims
1. A jig intended in use to hold a set of blanks of rod-like or
wire-like form during machining, said jig comprising a body adapted
to be mounted to a drive shaft for rotation of the body about an
axis of rotation, the body having an outer portion and an inner
portion wherein the inner and outer portions are capable of angular
displacement relative to each other, the portions having opposed
faces which are concentric and which define clamping faces which in
use are intended to support the set of blanks such that their
central axes are substantially parallel to the axis of rotation and
at least one end extends axially beyond the body.
2. A jig as claimed at claim 1 wherein the clamping faces are
defined by a set of stations located around the axis of rotation,
each station having a sector of the clamping face of each
portion.
3. A jig as claimed at claim 1 wherein one or more stations are
arranged around the axis of rotation.
4. A jig as claimed at claim 1 wherein the outer clamping face is
provided on the inner face of the outer portion and the inner
clamping face at each station is provided by a shoe member
supported from the inner portion, the shoe member having an arcuate
outer face which defines the inner clamping face.
5. A jig as claimed at claim 4 wherein the shoe member is supported
on the inner portion for radial movement relative to the outer
clamping face to effect clamping of the blanks between the opposed
clamping surfaces, a driving means between each shoe member and the
inner portion to bias the inner clamping face into clamping
engagement with the outer clamping face.
6. A jig as claimed at claim 5 wherein the driving means comprises
a set of springs.
7. A jig as claimed at claim 5 wherein the driving means comprises
a hydraulic drive.
8. A jig as claimed at claim 4 wherein said shoe member is
removable from the jig.
9. A jig as claimed at claim 1 wherein the surface jointly defined
by the clamping surfaces is cylindrical whereby the axes of the
blanks clamped therebetween will extend parallel to the axis of
rotation of the jig.
10. A jig as claimed at claim 1 wherein the surface jointly defined
by the clamping surfaces is conical whereby the axes of the blanks
clamped therebetween will have an inclination relative to the axis
of the jig.
11. (canceled)
Description
FIELD OF THE INVENTION
[0001] This present invention relates to the manufacture of
elongate elements which require a treatment such as machining,
grinding and like treatment. Such elongate items can include
hypodermic needles and other small diameter components such as
trephines or trocars, and more particularly to the machining of
hypodermic needles and other small diameter components from
blanks.
BACKGROUND
[0002] The lancing action of a hypodermic needle, often referred to
as a "blade", is generally facilitated by three bevels, or facets,
ground on an end portion of a tubular blank ("tube") from which the
blade is formed. These typically comprise a primary facet and two
secondary facets, resulting in the blade having three distinct
facet intersections when viewed axially. The sharpness of the angle
between these ground facets, between each facet and the blade's
curved surfaces, along with other factors such as the diameter and
thickness of the blade, effect the levels of patient comfort
experienced in use.
[0003] Despite the number of blades being consumed by the world's
populace continuously increasing over the last fifty years, the
manner in which they are mass-produced has developed little in the
same period. Typically a linear jig holding up to 1,000 tubes is
used. The tubes are clamped between two flat plates of the jig and
arranged adjacent one another such that their longitudinal axes are
parallel, with one end of each of the tubes extending out from the
jig in a direction orthogonal to the axis of a grinding wheel. The
amount each tube extends out is governed by such factors as the
tolerance of the grinding operation, the amount of material to be
removed, and the tube material and dimensions.
[0004] During grinding of the blades, the jig traverses the length
of the grinding wheel to progressively expose all of the tubes
clamped in the jig to the grinding wheel. The primary facet is
first ground adjacent the ends of all of the tubes, typically with
twelve traverses of the linear jig across the face of the grinding
wheel, advancing the jig closer to the grinding wheel at the
completion of each traverse. Next, one of the flat plates of the
jig clamping the tubes is moved relative to the other in a
direction orthogonal to the longitudinal axis of the tubes to roll
the tubes uniformly through a predetermined angle. This time with
only two traverses across the grinding wheel, a first secondary
facet is ground adjacent the end of each tube. The tubes are then
further rolled about their longitudinal axes through a
predetermined angle, and a further secondary facet having a shape
corresponding to the first secondary facet is ground, again in two
traverses.
[0005] Manufacturing blades by this process presents several
difficulties. The linear jig relies on achieving parallel alignment
of adjacent tubes, with the ends of the tubes between the clamping
plates extending out from the jig orthogonal to the longitudinal
axis of the grinding wheel, and a uniform clamping pressure being
applied to all of the tubes. Precise grinding further depends on
accurately rolling the tubes while maintaining this orthogonal
angle of the tubes to the grinding face of the grinding wheel.
Initial misalignment of the tubes results in inconsistencies
between blades ground in the same and different batches, and these
inconsistencies and errors are magnified when the tubes are rolled
between the grinding of the different facets. This initial
misalignment is both difficult to detect and to remedy, being
expensive in terms of time to correct, wasted tubes and/or reduced
or inadequate quality of the ground blades.
[0006] When manufacturing needles for use in certain types of
safety syringes that require a slit or flat to be machined in the
tube for co-operation with related structure in the body of the
syringe, the slit or flat requires a precise alignment with the
primary facet. Current practice for the machining of these slits or
flats is to employ another operation subsequent to the grinding of
the facets, wherein the blades are re-orientated for the further
machining operation. This makes the machining of the slits or flats
quite a time-consuming operation. This operation becomes further
complicated by the need to avoid touching the ground ends of the
tubes to determine the exact locations of the already ground
facets, as this has the adverse effect of blunting the ground facet
edges.
[0007] The conventional method of manufacturing blades using a
linear jig results in the grinding wheel having wear greater at its
axial end sections than at its middle section, resulting from the
horizontal traverses of the jig wherein the tubes first come into
contact with the wheel at the axial ends of the wheel. Hence, there
is a tendency for the grinding wheels to develop a tapered
sectional profile from the middle to either end of the wheels which
in turn means that the grinding wheels need to be regularly dressed
back to a cylindrical profile.
[0008] Further, because grinding occurs largely at the two regions
adjacent the axial ends of the grinding wheel, there is a tendency
for the temperature of the grinding wheel to build up at these
regions, even with the substantive use of coolants. With continuous
grinding, these "hot spots" can result in the grinding wheel
wearing down quicker and a glazing of the grinding wheel in these
regions causing possibly the burning of the blades around the
regions of the ground facets, and necessitating further dressing of
the wheel thus reducing the life of the wheel.
[0009] Typically, for each batch of tubes sixteen traverses of the
longitudinal length of the grinding wheel by the linear jig are
required for grinding the primary and secondary facets. After each
traverse of the linear jig across the grinding wheel the linear jig
must be stopped and restarted in the opposite direction. This
substantive number of traverses of the linear jig, in combination
with the stop/start nature of these traverses, makes it a
relatively inefficient process.
[0010] The above description in relation to the background of the
manufacture of hypodermic needles is not intended to be limiting on
the scope of the invention but is merely for the purposes of
enhancing an understanding of the present invention.
[0011] The reference to any prior art in this specification is not,
and should not be taken as, an acknowledgement or any form of
suggestion that that prior art forms part of the common general
knowledge in Australia or the world.
DISCLOSURE OF THE INVENTION
[0012] Accordingly the invention resides in a jig intended in use
to hold a set of blanks of rod-like or wire-like form during
machining, said jig having a body adapted to be mounted to a drive
shaft for rotation of the body about an axis of rotation, the body
having an outer portion and an inner portion wherein the inner and
outer portions are capable of angular displacement relative to each
other, the portions having opposed faces which are concentric and
which define clamping faces which in use are intended to support
the set of blanks such that their central axes are substantially
parallel to the axis of rotation and at least one end extends
axially beyond the body.
[0013] According to a preferred feature of the invention the
clamping faces are defined by a set of stations located around the
axis of rotation, each station having a sector of the clamping face
of each portion.
[0014] According to a preferred feature of the invention, one or
more stations are arranged around the axis of rotation.
[0015] According to a preferred feature of the invention, the outer
clamping face is provided on the inner face of the outer portion
and the inner clamping face at each station is provided by a shoe
member supported from the inner portion, the shoe member having an
arcuate outer face which defines the inner clamping face.
[0016] According to a preferred feature of the invention the shoe
member is supported on the inner portion for radial movement
relative to the outer clamping face to effect clamping of the
blanks between the opposed clamping surfaces, a biasing means
between each shoe member and the inner portion to bias the inner
clamping face into clamping engagement with the outer clamping
face. According to a preferred feature of the invention the driving
means comprises a set of springs. According to an alternative
preferred feature of the invention the driving means comprises a
hydraulic drive.
[0017] According to a preferred feature of the invention said shoe
member is removable from the jig.
[0018] According to a preferred feature of the invention the
surface jointly defined by the clamping surfaces is cylindrical
whereby the axes of the blanks clamped therebetween will extend
parallel to the axis of rotation of the jig. According to
alternative preferred features of the invention the surface jointly
defined by the clamping surfaces may be conical whereby the axes of
the blanks clamped therebetween will have an inclination relative
to the axis of the jig.
[0019] The rotary jig according to the invention is not restricted
to use in grinding blanks for forming hypodermic needles, but also
has a more general applicability for use in machining blanks for
other uses, such as surgical lances, trephines or trocars. In
addition the invention can have application to the machining of any
form of elongate element and need not be restricted to the
production of items intended for medical use. Machining operations
which can be carried out while the blanks are held by the jig can
include, grinding, laser cutting, waterjet cutting and milling.
[0020] The invention will be more fully understood in the light of
the following description of several specific embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The description is made with reference to the accompanying
drawings, of which:
[0022] FIG. 1 is an exploded perspective view of a rotary jig
according to the first embodiment of the present invention;
[0023] FIG. 2 is an isometric view of the front face of the jig
according to the first embodiment; and
[0024] FIG. 3 is an isometric view of the rear face of the jig
according to the first embodiment.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
[0025] The first embodiment is directed to a development of one of
the embodiments described in International application
PCT/AU2004/000090.
[0026] The first embodiment comprises a jig which can be utilised
in the manufacture of needle blanks for the introduction of needles
which can be used with hypodermic syringes. The jig according to
the embodiment is intended for use with a drive of the form
disclosed in copending patent application filed this day in the
name of the applicant which is entitled "Drive" the contents of
which are included by reference.
[0027] The jig comprises two portions being an outer portion 11 and
an inner portion 13 which are capable of rotation about a central
axis relative to each other. The outer portion comprises an annular
rim 15 which is supported from a first yoke comprising three arms
17 interconnected at the centre 19 of the jig. The centre of the
first yoke is adapted to be mounted to the drive shaft of the
drive. The inner portion comprises a second yoke 21 which is of a
generally triangular configuration and which is rotationally
supported from first yoke through a hub assembly 23.
[0028] The faces of the second yoke 21 each support a clamping shoe
25 which has an outer arcuate face 27 which is intended to be in
opposed relationship with the inner face of the rim 15 whereby the
inner face of the rim 15 and the arcuate face 27 of the clamping
shoes 25 define the clamping surfaces. Each shoe is supported from
the respective face of the inner yoke by a pair of spaced locking
members 29 and the pins are supported from the second yoke to be
slidable inwardly and outwardly from the respective face. The pins
of each locking member are biased to their outermost position by
springs or other biasing means which are received around each of
the pins. The outermost ends of each of the pins are formed with a
head which is receivable in apertures 31 provided on the inner face
of the shoes 31. With axial retraction of the pins against the
biasing force provided by the springs or other biasing means the
pins are withdrawn from engagement with the apertures provided on
the inner face of the shoe to enable the shoes to be removed from
the jig.
[0029] Each of the shoes is further provided with an axial opening
which is intended to be received by a retaining peg member provided
on the drive head of the drive with which the jig is to be
associated and which are to positively engage with the inner
portion to effect of rotation of the inner portions and shoes
relative to the outer rim.
[0030] In use the jig is intended to be removable from the drive
head and the shoes are removable from the jig by retraction of the
pins 29. When the shoe has been removed the needle blanks can the
be applied to the outer arcuate face 27 of the shoe and retained in
place by a suitable adherent. With the needles in place the shoe
can then be located into supporting relationship on the second yoke
21 and the pins engaged with the inner face of the shoe member to
bias the shoe member into clamping engagement with the outer rim 15
and thereby retain the needles in place.
[0031] In use it is intended that the mounting and dismounting of
the jig from the drive can be effected by utilisation of a suitable
robot facility which would then be able to deliver the jigs to a
delivery station at which the shoe members can be removed and
freshly loaded shoes installed in the jig for relocation into the
drive.
[0032] While the rotary jig 11 according to the embodiment
described above is particularly suited to the grinding of tubes for
use as hypodermic needles, the use of the rotary jig according to
each of the embodiments and the invention are not limited to the
such. The rotary jig according to the embodiment and the invention
can be used in processing of rod or tube-like members and can be
used in association with any suitable grinding arrangement or an
arrangement utilising any other applicable form of machining and
grinding such as laser cutting, waterjet cutting, or milling.
[0033] According to a second embodiment of the invention the pins
29 of the first embodiment are driven hydraulically. To effect this
the second yoke 21 is provided with chambers which are associated
with a master piston which is actuable form the exterior of the
yoke to be movable into and out of the chamber and each of the pins
29 are formed at their inner end to be in the form of slave pistons
whereby they will move in accordance with the action of the master
piston. The master piston is caused to move through a drive screw
which is threadably supported by the yoke and which can bear on the
master piston. In addition the driving axis of the pins for each
shoe is substantially parallel to the central radial axis of the
shoe.
[0034] The embodiment of the present invention has been described
by way of example only and modifications and variations may be made
without departing from the spirit and scope of the invention
described.
[0035] Throughout the specification, unless the context requires
otherwise, the word "comprise", and variations such as "comprises"
or "comprising", will be understood to imply the inclusion of a
stated step or integer or group of steps or integers but not the
exclusion of any other step or integer or group of steps or
integers.
* * * * *